The external policy of Byzantium during the reigns of the Andronicoi

The external policy of Andronicus II and Andronicus III, grandfather and grandson, differed from that of their predecessor, Michael VIII. A great danger had menaced Michael from the West, from Charles to Anjou; but the Sicilian Vespers had removed that danger forever in the year of Michael's death. The Turks had been prevented by their own troubles from making adequate use of their advantageous position on the eastern border of the Empire.

Andronicus II and Andronicus III had to face two new and strong foes: Serbia in the Balkan peninsula and the Ottoman Turks in Asia Minor. Like Charles of Anjou, the rulers of these two peoples had set as their definite goal in the struggle with Byzantium, the complete destruction of the Empire and the formation on its site of either a Greco-Slavonic or a Greco-Turkish Empire. Charles' plan to establish the Greco-Latin Empire had failed. In the fourteenth century the great king of Serbia, Stephen Dushan (Dusan), seemed to be on the point of establishing a great Slavonic empire. But for many reasons only the Ottoman Turks were to succeed in carrying out this plan: in the middle of the fifteenth century they were to establish an enormous empire, not only Greco-Turkish, but Greco-Slavo-Turkish, controlling both the Serbs and the Bulgars.